In a cellular wireless communication system, radio resources are shared between adjacent cells. Therefore, interference occurs to different UEs located in the adjacent cells in the cellular wireless environment, thereby rapidly decreasing the performance of cell-edge UEs. Despite the same channel gain, the capacity of a cell-edge UE is rapidly changed depending on whether a UE uses the same resources in a neighbor cell. In general, the capacity of a channel is determined byC=log2(1+|h|2×SINR)  [Equation 1]where C represents the channel capacity, |h| represents a channel gain, and SINR represents a signal to interference and noise ratio.
That is, no matter how good the channel is, the actual capacity that the UE can achieve is determined by the SINR of a signal received from a BS. This relationship similarly applies to downlink as well as uplink. For example, when the BS transmits a signal to a cell-edge UE, interference from a neighbor cell limits the total capacity of the UE as in [Equation 1], even though the channel between the UE and the BS is in good state.
To avert this problem, a wireless communication system allocates resources to adjacent cells through fractional frequency reuse, fixed reuse, etc. such that they are not overlapped between the adjacent cells. That is, an environment is built in which radio resources used by a specific cell-edge UE are not used in a neighbor cell. Aside from a method for limiting use of radio resources, soft frequency reuse is also considered, which has the same effects only through power control. Although soft frequency reuse is similar to fractional frequency reuse, the former may provide a service to UEs within a cell by reducing power in a frequency area overlapped with the neighbor cell, rather than the frequency area is not used at all. However, if frequency resources are segmented for each cell, the total bandwidth of the system is decreased, which limits an achievable maximum throughput irrespective of the actual situation of the neighbor cell. On the other hand, SDMA (spatial diversity multiple access) using multiple antennas is under consideration. In SDMA, interference can be reduced by receiving a target signal with interference from the neighbor cell minimized through beamforming according to the location of a UE. However, its complex signaling and imperfect coordination may lead to the degradation of overall performance. The most passive method for handling neighbor cell interference is to design radio resources into a cell-specific configuration for each cell. However, this method is effective only when each cell has a small amount of traffic, but does not present a basic solution to interference.